general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 6148 Comm: syz.1.185 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS:  000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 do_vcc_ioctl+0x383/0x9e0 net/atm/ioctl.c:159
 sock_do_ioctl+0xfc/0x310 net/socket.c:1220
 sock_ioctl+0x5be/0x7e0 net/socket.c:1341
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f8e4b19e159
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff57650b68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f8e4b425fa0 RCX: 00007f8e4b19e159
RDX: 0000000000000000 RSI: 0000000000006180 RDI: 0000000000000003
RBP: 00007f8e4b23506b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8e4b425fac R14: 00007f8e4b425fa0 R15: 00007f8e4b425fa0
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:atmtcp_attach drivers/atm/atmtcp.c:408 [inline]
RIP: 0010:atmtcp_ioctl+0x84e/0xdd0 drivers/atm/atmtcp.c:477
Code: ff e9 bf fb ff ff 4c 8d 63 20 4c 89 e0 48 c1 e8 03 80 3c 28 00 74 08 4c 89 e7 e8 7d 98 83 fb 4d 8b 24 24 4c 89 e0 48 c1 e8 03 <80> 3c 28 00 74 08 4c 89 e7 e8 64 98 83 fb 49 83 3c 24 00 0f 84 e1
RSP: 0018:ffffc90004ed7c58 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff88806b290000 RCX: ffffffff8a99ef04
RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffc90004ed7ba0
RBP: dffffc0000000000 R08: ffffc90004ed7ba7 R09: 1ffff920009daf74
R10: dffffc0000000000 R11: fffff520009daf75 R12: 0000000000000000
R13: 1ffff1100d652000 R14: ffff8880778b8600 R15: ffff88807bc57000
FS:  000055556ac18500(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff36906ff8 CR3: 0000000076b77000 CR4: 00000000003506f0
----------------
Code disassembly (best guess):
   0:	ff                   	ljmp   (bad)
   1:	e9 bf fb ff ff       	jmp    0xfffffbc5
   6:	4c 8d 63 20          	lea    0x20(%rbx),%r12
   a:	4c 89 e0             	mov    %r12,%rax
   d:	48 c1 e8 03          	shr    $0x3,%rax
  11:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1)
  15:	74 08                	je     0x1f
  17:	4c 89 e7             	mov    %r12,%rdi
  1a:	e8 7d 98 83 fb       	call   0xfb83989c
  1f:	4d 8b 24 24          	mov    (%r12),%r12
  23:	4c 89 e0             	mov    %r12,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 28 00          	cmpb   $0x0,(%rax,%rbp,1) <-- trapping instruction
  2e:	74 08                	je     0x38
  30:	4c 89 e7             	mov    %r12,%rdi
  33:	e8 64 98 83 fb       	call   0xfb83989c
  38:	49 83 3c 24 00       	cmpq   $0x0,(%r12)
  3d:	0f                   	.byte 0xf
  3e:	84 e1                	test   %ah,%cl